Present embodiments relate generally to gas turbine engines. More particularly, but not by way of limitation, present embodiments relate to a fast response temperature sensor using an enclosed resistance temperature detector (RTD).
A typical gas turbine engine generally possesses a forward end and an aft end with its several core or propulsion components positioned axially therebetween. An air inlet or intake is at a forward end of the engine. Moving toward the aft end, in order, the intake is followed by a compressor, a combustion chamber, a turbine, and a nozzle at the aft end of the engine. It will be readily apparent from those skilled in the art that additional components may also be included in the engine, such as, for example, low-pressure and high-pressure compressors, and high-pressure and low-pressure turbines. This, however, is not an exhaustive list. An engine also typically has an internal shaft axially disposed along a center longitudinal axis of the engine. The internal shaft is connected to both the turbine and the air compressor, such that the turbine provides a rotational input to the air compressor to drive the compressor blades.
In operation, air is pressurized in a compressor and mixed with fuel in a combustor for generating hot combustion gases which flow downstream through turbine stages. These turbine stages extract energy from the combustion gases. A high pressure turbine first receives the hot combustion gases from the combustor and includes a stator nozzle assembly directing the combustion gases downstream through a row of high pressure turbine rotor blades extending radially outwardly from a supporting rotor disk. In a two stage turbine, a second stage stator nozzle assembly is positioned downstream of the first stage blades followed in turn by a row of second stage rotor blades extending radially outwardly from a second supporting rotor disk. The turbine converts the combustion gas energy to mechanical energy. The second stage turbine blades and rotor disk are mechanically coupled to a low pressure or booster compressor for driving the booster compressor and additionally an inlet fan.
During the operation of the gas turbine engine, it is necessary to obtain temperature readings at different locations in the engine. This data is utilized by the engine control logic to properly operate the engine and provide maximum performance at the highest efficiency. These probes utilize thermocouples, typically having a dissimilar metal to create a differential which may be then related to a temperature and which is provided to the engine control logic. These probes utilize type-K thermocouples typically having dissimilar metals to create a differential which may be then input to the engine control logic to optimize performance.
Some designs of fast response RTDs have had performance problems associated with conduction error due to large housing and/or because the RTD is encased in potting material. The housing or potting material increases the mass of the device and increases the path for heat to be transmitted to the sensor causing error. The errors in the sensors result in poor data being provided to engine control systems and less efficient engine operations.
As may be seen by the foregoing, it would be desirable to overcome these and other deficiencies with RTDs used in gas turbine engines so as to produce faster and more accurate temperature readings.
The information included in this Background section of the specification, including any references cited herein and any description or discussion thereof, is included for technical reference purposes only and is not to be regarded subject matter by which the scope of the innovation is to be bound.